1. Field
Embodiments relate to a battery management system managing a battery by estimating a state of charge (SOC) of a rechargeable/dischargeable rechargeable battery, and a method for estimating a battery SOC.
2. Description of the Related Art
A vehicle that uses an internal combustion engine, which uses gasoline or diesel oil as a main fuel, has caused serious environmental pollution, such as air pollution. Consequently, in order to reduce the amount of environmental pollution, efforts have been made to develop electric vehicles or hybrid vehicles.
The electric vehicle uses an electric engine that is powered by electrical energy output from a battery. The electric vehicle uses a battery having a plurality of rechargeable battery cells formed into one pack as a main power source. Therefore, the electric vehicle does not exhaust gas or produce loud noises.
A hybrid vehicle is a cross between a vehicle using an internal combustion engine and an electric vehicle. The hybrid vehicle uses two or more kinds of power sources, e.g., an internal combustion engine and an electric engine. Currently, a complex hybrid car, such as a hybrid car that uses the internal combustion engine and fuel cells, which directly obtain electrical energy by causing a chemical reaction while continuously supplying hydrogen and oxygen, or a hybrid car that uses the battery and the fuel cells, has been developed.
The performance of the vehicle using the electrical energy is directly affected by the performance of the battery. Therefore, each battery cell needs to have high performance. Furthermore, a battery management system has been required to efficiently manage the charging and discharging of the battery cells. The conventional battery management system estimates the SOC by ampere counting or by relying on previously determined relationship between the SOC and elements, e.g., an open circuit voltage (OCV), a discharge voltage, an internal resistance, a temperature, or a discharge current.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.